Field of the Invention
The invention relates to an electric connector array, including a knife strip and a spring strip of insulating material, each having a plurality of signal contacts being disposed in columns and rows and being connectable to one another by being plugged together, and each individual signal contact being shielded on all sides by sheet-metal elements.
Low-frequency printed wiring board plug connectors are increasingly being operated with faster digital signals. Very steep leading edges of the signals correspond with high frequencies. That creates problems in terms of the quality of signal transmission and in particular, undesirable crosstalk effects occur between adjacent signal contacts.
Conventionally, the problem of crosstalk can be solved by passing the signals through only every other contact, while the intervening contacts are occupied by ground. In that solution, however, the number of terminals that are usable for signal transmission is drastically reduced, and therefore that solution hardly appears useful for applications involving a high signal density.
It is known from German Patent DE 40 40 551 C2, corresponding to U.S. Pat. No. 5,104,341, to prevent crosstalk between adjacent terminals in adjacent vertical rows by inserting a shielding element between the vertical terminal rows of a spring strip. A disadvantage in that case, however, is that of the five available rows of contacts, only three rows are usable for signals, while two rows are occupied by ground. Published European Patent Application 0 486 298 A1 on the other hand discloses a connector array in which ground contacts are each disposed between the signal contacts while being offset by one-half the period, so that in the assembled state the signal contacts are surrounded by ground contacts. That device again is not ideal, because the individual contacts for carrying the ground are all contacted individually, thus making routing of the signals considerably more difficult.
A member of the 2.5 mm "SIPAC" plug connector family in accordance with the structure mentioned initially above has become known from a publication entitled: Markt und Technik--Wochenzeitung fur Elektronik [Market and Industry--Weekly Newspaper of Electronics], No. 26, Jun. 24, 1994, pp. 36-37. In that device, however, continuous shielding of each individual contact is carried out with a tight, square metal shaft. A "compartment structure" of lengthwise and crosswise metal sheets or plates that are required for this shaft and are spaced apart from one another by 2.5 mm, is located entirely inside the spring strip. Slits must therefore be provided at the points of penetration of the crosswise and lengthwise sheets or plates. The slits intermesh with one another and make a high-quality electrical contact with one another.